The shell loading sound of a pump shotgun in the dark, says two things. I have a shotgun, and I probably won’t miss.
“I have a shotgun, and I probably wont miss.”
Also, “here I am”.
I’m not interested in communicating with threats, I’m interested in ending them.
Per implied scenario: someone has already made the deliberate choice to, against all law & social rules, cause damage and enter my home and prowl in the dark and steal and likely intends to do much worse - all with the knowledge that I may very well respond with deadly force, so he is likely prepared to accept combat with expectation of prevailing. This is not someone to have a “I have a shotgun and probably won’t miss” conversation with (revealing my location, intent, and ability), this is someone to inflict a decisive blow upon at the earliest possible opportunity, facilitated by maximum stealth/surprise. This is Condition Red: there is a lethal threat at hand, terminate it.